Method of signaling control information in wireless communication system with multiple frequency blocks

ABSTRACT

A method for performing communication in a user equipment of a wireless communication system comprises receiving a control region through a specific frequency block of a plurality of frequency blocks, the control region including a plurality of control channels; identifying a first control channel for the user equipment in the control region; and performing an operation in accordance with information included in the first control channel, wherein the specific frequency block through which the first control channel is transmitted is changed according to a certain pattern with the lapse of time.

DETAILED DESCRIPTION OF THE INVENTION

1. Technical Field

The present invention relates to a wireless communication system thatuses a plurality of frequency blocks. The wireless communication systemcan support at least one of single carrier-frequency division multipleaccess (SC-FDMA), multi carrier-frequency division multiple access(MC-FDMA), and orthogonal frequency division multiple access (OFDMA).The wireless communication system can also support at least one offrequency division duplex (FDD), half-FDD (H-FDD), and time divisionduplex (TDD). More particularly, the present invention relates to amethod of signaling control information in the wireless communicationsystem.

2. Background Art

FIG. 1A illustrates a network structure of an Evolved Universal MobileTelecommunications System (E-UMTS). The E-UMTS system is an evolvedversion of the conventional WCDMA UMTS system and standardizationthereof is in progress under the 3rd Generation Partnership Project(3GPP). The E-UMTS is also referred to as a Long Term Evolution (LTE)system. For details of the technical specifications of the UMTS andE-UMTS, refer to Release 7 and Release 8 of “3rd Generation PartnershipProject; Technical Specification Group Radio Access Network”.

Referring to FIG. 1A, the E-UMTS includes a User Equipment (UE), a basestation, and an Access Gateway (AG) which is located at an end of anetwork (E-UTRAN) and connected to an external network. Generally, thebase station can simultaneously transmit multiple data streams for abroadcast service, a multicast service and/or a unicast service. The AGcan be divided into a part that handles processing of user traffic and apart that handles control traffic. In this case, the AG part forprocessing new user traffic and the AG part for processing controltraffic can communicate with each other using a new interface. One ormore cells may exist for one eNode B (eNB). One cell constituting eNB isset to one of bandwidths of 1.25, 2.5, 5, 10, and 20 Mhz to provide adownlink or uplink transport service to several user equipments. Also,in a wireless communication system, one base station controls datatransmission and reception for a plurality of user equipments. The basestation transmits downlink scheduling information of downlink data tothe corresponding user equipment to notify time and frequency domains towhich data will be transmitted and information related to encodingscheme, data size, hybrid automatic repeat and request (HARQ). Also, thebase station transmits uplink scheduling information of uplink data tothe corresponding user equipment to notify time and frequency domainsthat can be used by the corresponding user equipment, and informationrelated to encoding scheme, data size, HARQ. Different cell can beestablished to provide different bandwidths. An interface fortransmitting user traffic or control traffic can be used between eNBs. ACore Network (CN) may include the AG and a network node or the like foruser registration of the UE. An interface for discriminating between theE-UTRAN and the CN can be used. The AG manages mobility of a UE on aTracking Area (TA) basis. One TA includes a plurality of cells. When theUE has moved from a specific TA to another TA, the UE notifies the AGthat the TA where the UE is located has been changed.

FIG. 1B illustrates a network structure of an Evolved UniversalTerrestrial Radio Access Network (E-UTRAN) system. The E-UTRAN system isan evolved version of the conventional UTRAN system. The E-UTRANincludes base stations that will also be referred to as “eNode B” or“eNB”. The eNBs are connected with each other through an X2 interface.X2 user plane interface (X2-U) is defined between the eNBs. The X2-Uinterface provides non-guaranteed delivery of a user plane PDU. X2control plane interface (X2-CP) is defined between two neighboring eNBs.The X2-CP performs context transfer between eNBs, control of a userplane tunnel between a source eNB and a target eNB, transfer of handovermessage, and uplink load management. The eNB is connected to the UserEquipment (UE) through a radio interface and is connected to an EvolvedPacket Core (EPC) through a S1 interface. S1 user plane interface (SI-U)is defined between the eNB and a serving gateway (S-GW). S1 controlplane interface is defined between the eNB and a mobility managemententity (MME). The S1 interface performs bearer service management of anevolved packet system (EPS), non-access stratum (NAS) signalingtransport, network sharing, MME load balancing, etc.

DESCRIPTION OF THE INVENTION Technical Problems

Although wireless communication technology developed based on WCDMA hasbeen evolved into LTE, request and expectation of users and providershave continued to increase. Also, since another wireless accesstechnology is being continuously developed, new evolution of thewireless communication technology is required for competitiveness in thefuture. In this respect, reduction of cost per bit, increase ofavailable service, use of adaptable frequency band, simple structure,open type interface, proper power consumption of user equipment, etc.are required.

Recently, standardization of advanced technology of LTE is in progressunder the 3rd Generation Partnership Project (3GPP). This technologywill be referred to as “LTE-Advance” or “LTE-A.” One of importantdifferences between the LTE system and the LTE-A system is difference insystem bandwidth. The LTE-A system aims to support a wideband of maximum100 MHz. To this end, the LTE-A system uses carrier aggregation orbandwidth aggregation that achieves a wideband using a plurality offrequency blocks. A bandwidth of each frequency block can be definedbased on a bandwidth of a system block used in the LTE system.

In this respect, it is required to efficiently design a control channelin a communication system that supports a wideband. Moreover, since auser equipment of the existing LTE system and a user equipment of theLTE-A system coexist in the LTE-A system, it is preferably required todesign a control channel considering both of the user equipments. Also,a method of configuring control information under a communication systemthat supports a wideband is required.

Accordingly, the present invention is directed to a method of signalingcontrol information in a wireless communication system with multiplefrequency blocks, which substantially obviates one or more problems dueto limitations and disadvantages of the related art.

An object of the present invention is to provide a method of efficientlyproviding a control channel in a wideband communication system.

Another object of the present invention is to provide a method ofefficiently providing a control channel in a wireless communicationsystem that supports a plurality of frequency blocks.

Other object of the present invention is to provide a method ofefficiently configuring control information in a wideband communicationsystem.

It is to be understood that technical problems to be solved by thepresent invention are not limited to the aforementioned technicalproblems and other technical problems which are not mentioned will beapparent from the following description to the person with an ordinaryskill in the art to which the present invention pertains.

Technical Solutions

In one aspect of the present invention, a method for performingcommunication in a user equipment of a wireless communication systemcomprises receiving a control region through a specific frequency blockof a plurality of frequency blocks, the control region including aplurality of control channels; identifying a first control channel forthe user equipment in the control region; and performing an operation inaccordance with information included in the first control channel,wherein the specific frequency block through which the first controlchannel is transmitted is changed according to a certain pattern withthe lapse of time.

In another aspect of the present invention, a user equipment forperforming communication using a plurality of frequency blocks comprisesa radio frequency (RF) module configured to transmit or receive a signalthrough the plurality of frequency blocks; and a processor configured toprocess the signal received from the RF module per frequency block,wherein the RF module receives a control region through a specific oneof the plurality of frequency blocks, the control region including aplurality of control channels, the processor identifies a first controlchannel for the user equipment in the control region and performs anoperation in accordance with information included in the first controlchannel, and the specific frequency block through which the controlregion is transmitted is changed according to a certain pattern with thelapse of time.

The wireless communication system supports carrier aggregation orbandwidth aggregation. In this case, a bandwidth of each frequency blockis established independently. Also, a bandwidth of each frequency blockis established based on a system bandwidth defined in a legacy system.For example, each frequency block has the same size as that of a systemblock defined in the legacy system. If the legacy system is 3GPP LTEsystem, a bandwidth of each frequency block has any one of 1.25, 2.5, 5,10, 20 MHz, and their multiple numbers. Also, at least one of aplurality of frequency blocks, preferably one frequency block is used asa legacy system block that supports a legacy user equipment.

In this case, center carriers of the respective frequency blocks areestablished differently from one another.

The control region is configured by one or more consecutive orthogonalfrequency division multiple access (OFDMA) symbols. For example, thecontrol region is configured by one to three consecutive OFDM symbols.

The step of identifying the first control channel includes identifying acontrol channel search space established within the control region, thecontrol channel search space being configured by some of all controlchannels.

The control channel search space includes one or more control channelelements (CCEs).

The information included in the first control channel includesscheduling information. In this case, data are transmitted and receivedthrough a scheduled one of the plurality of frequency blocks, and thespecific frequency block is different from the scheduled frequencyblock.

The certain pattern is shared between the user equipment and, a basestation. In this case, the certain pattern is shared between the userequipment and the base station through an index indicating a specificpattern. Also, the certain pattern is determined indirectly usingspecific information shared between the user equipment and the basestation. The specific information includes at least one of identifierfor identifying the user equipment, identifier for identifying the basestation, available frequency bandwidths, and the number of availablefrequency blocks.

ADVANTAGEOUS EFFECTS

According to the embodiments of the present invention, the followingadvantages can be obtained.

First of all, in a wideband communication system, a control channel isprovided efficiently.

Second, in a wireless communication system that uses a plurality offrequency blocks, a control channel is provided efficiently.

Finally, a method of efficiently configuring control information in awideband communication system is provided.

It is to be understood that the advantages that can be obtained by thepresent invention are not limited to the aforementioned advantages andother advantages which are not mentioned will be apparent from thefollowing description to the person with an ordinary skill in the art towhich the present invention pertains.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a diagram illustrating a wireless communication system;

FIG. 2 is a diagram illustrating a structure of a radio frame used in3GPP LTE;

FIG. 3 is a diagram illustrating a resource grid of a downlink slot;

FIG. 4 is a diagram illustrating a functional structure of a downlinkradio frame;

FIG. 5 is a diagram illustrating a control channel included in a controlregion of a subframe;

FIG. 6 is a diagram illustrating a resource allocation unit of a controlchannel;

FIG. 7 is a diagram illustrating an example of a control channel element(CCE) distributed into a system band;

FIG. 8 is a diagram illustrating carrier aggregation;

FIG. 9 to FIG. 11 are block diagrams illustrating a transmitter and areceiver for carrier aggregation;

FIG. 12 is a diagram illustrating a structure of a radio frame to whichcarrier aggregation is applied;

FIG. 13 to FIG. 15 are diagrams illustrating examples of establishing aphysical downlink control channel (PDCCH) search space in accordancewith one embodiment of the present invention;

FIG. 16 is a diagram illustrating an example of mapping a controlchannel with each frequency block in accordance with one embodiment ofthe present invention;

FIG. 17 is a diagram illustrating an example of establishing a physicaldownlink control channel (PDCCH) search space within a plurality offrequency blocks in accordance with one embodiment of the presentinvention;

FIG. 18 is a diagram illustrating an example of transmitting orreceiving data to and in a user equipment in accordance with controlinformation in accordance with one embodiment of the present invention;

FIG. 19 to FIG. 24 are diagrams illustrating an example of configuringscheduling information for a plurality of frequency blocks in accordancewith one embodiment of the present invention; and

FIG. 25 is a diagram illustrating a transceiver that can be applied toone embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, structures, operations, and other features of the presentinvention will be understood readily by the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Embodiments described later are examples in which technicalfeatures of the present invention are applied to 3GPP system.

Hereinafter, a system that includes a system band of a single frequencyblock will be referred to as a legacy system or a narrowband system. Bycontrast, a system that includes a system band of a plurality offrequency blocks and uses at least one or more frequency blocks as asystem block of a legacy system will be referred to as an evolved systemor a wideband system. The frequency block used as a legacy system blockhas the same size of the system block of the legacy system. On the otherhand, there is no limitation in sizes of the other frequency blocks.However, for system simplification, the sizes of the other frequencyblocks may be determined based on the size of the system block of thelegacy system. For example, the 3GPP LTE (Release-8) system and the 3GPPLTE-A (Release-9) system are a legacy system and its evolved system.

Based on the aforementioned definition, the 3GPP LTE (Release-8) systemwill herein be referred to as an LTE system or the legacy system. Also,a user equipment that supports the LTE system will be referred to as anLTE user equipment or a legacy user equipment. The 3GPP LTE-A(Release-9) system will be referred to as an LTE-A system or an evolvedsystem. Also, a user equipment that supports the LTE-A system will bereferred to as an LTE-A user equipment or an evolved user equipment.

For convenience, although the embodiment of the present invention willbe described based on the LTE system and the LTE-A system, the LTEsystem and the LTE-A system are only exemplary and can be applied to allcommunication systems corresponding to the aforementioned definition.Also, although the embodiment of the present invention will herein bedescribed based on FDD mode, the FDD mode is only exemplary and theembodiment of the present invention can easily be applied to H-FDD modeor TDD mode.

FIG. 2 is a diagram illustrating a structure of a radio frame used in3GPP LTE.

Referring to FIG. 2, the radio frame has a length of 10 ms(327200·T_(s)) and includes 10 subframes of an equal size. Each subframe has a length of 1 ms and includes two slots. Each slot has alength of 0.5 ms (15360·T_(s)). In this case, T_(s) represents asampling time, and is expressed by T_(s)=1/(15kHz×2048)=3.2552×10⁻⁸(about 33 ns). The slot includes a plurality ofOFDM symbols in a time region, and includes a plurality of resourceblocks (RBs) in a frequency region. A transmission time interval (TTI)which is a transmission unit time of data can be determined in a unit ofone or more subframes. The aforementioned structure of the radio frameis only exemplary, and various modifications can be made in the numberof subframes included in the radio frame or the number of slots includedsubframes, or the number of OFDM symbols included in the slot.

FIG. 3 is a diagram illustrating a resource grid of a downlink slot.

Referring to FIG. 3, the downlink slot includes N_(symb) ^(DL) number ofOFDM symbols in a time region and N_(RB) ^(DL) number of resource blocksin a frequency region. Since each resource block includes N_(sc) ^(RB)number of subcarriers, the downlink slot includes N_(RB) ^(DL)×N_(sc)^(RB) number of subcarriers in the frequency region. Although an exampleof FIG. 3 illustrates that the downlink slot includes seven OFDM symbolsand the resource block includes twelve subcarriers, the presentinvention is not limited to the example of FIG. 3. For example, thenumber of OFDM symbols included in the downlink slot can be varieddepending on a length of cyclic prefix (CP). Each element on theresource grid will be referred to as a resource element (RE). The RE isa minimum time/frequency resource defined in a physical channel, and isindicated by one OFDM symbol index and one subcarrier index. Oneresource block includes N_(symb) ^(DL)×N_(sc) ^(RB) number of REs. Thenumber N_(RB) ^(DL) of resource blocks included in the downlink issubjected to a downlink transmission bandwidth established in a cell.

FIG. 4 is a diagram illustrating a functional structure of a downlinkradio frame.

Referring to FIG. 4, the downlink radio frame includes ten subframeshaving an equal length. In the 3GPP LTE system, the subframes aredefined as a basic time unit of packet scheduling for all downlinkfrequencies. Each subframe is divided into a control region fortransmission of scheduling information and other control information anda data region for transmission of downlink data. The control regionstarts from the first OFDM symbol of the subframes and includes one ormore OFDM symbols. The control region can have a size set independentlyper subframe. The control region is used to transmit L1/L2 (layer1/layer 2) control signals. The data region is used to transmit downlinktraffic.

FIG. 5 is a diagram illustrating a control channel included in a controlregion of a subframe.

Referring to FIG. 5, the subframe includes fourteen (14) OFDM symbols.First one to three OFDM symbols are used as the control region inaccordance with establishment of subframe, and other thirteen to elevenOFDM symbols are used as the data region. In FIG. 5, R1 to R4 representreference signals (RS) or pilot signals of antennas 0 to 3. The RS isfixed by a given pattern within the subframe regardless of the controlregion and the data region. The control channel is allocated to aresource to which the RS is not allocated in the control region, and thetraffic channel is also allocated to a resource to which the RS is notallocated in the data region. Examples of the control channel includePCFICH (Physical Control Format Indicator CHannel), PHICH (PhysicalHybrid-ARQ Indicator CHannel), and PDCCH (Physical Downlink ControlCHannel).

The PCFICH notifies the user equipment of the number of OFDM symbolsused in the PDCCH per subframe. The PCFICH is located in the first OFDMsymbol and established prior to the PHICH and the PDCCH. The PCFICHincludes four resource element groups (REG), each REG being distributedin the control region based on cell identity (cell ID). One REG includesfour REs. The structure of the REG will be described in detail withreference to FIG. 6. The PCFICH value indicates value of 1 to 3 or valueof 2 to 4 depending on a bandwidth, and is modulated by Quadrature PhaseShift Keying (QPSK).

The PHICH is used to transmit HARQ ACK/NACK signals for uplinktransmission. The PHICH includes three REGs, and is cell-specificallyscrambled. The ACK/NACK signals are indicated by 1 bit, and are spreadby a spreading factor (SF)=2 or 4, wherein spread signal is repeatedthree times. A plurality of PHICHs can be mapped with the same resource.The PHICH is modulated by Binary Phase Shift Keying (BPSK).

The PDCCH is allocated to first n number of OFDM symbols of thesubframe, wherein n is an integer and is indicated by the PCIFCH. ThePDCCH includes one or more CCEs, which will be described in detaillater. The PDCCH notifies each user equipment or user equipment group ofinformation related to resource allocation of transport channels, i.e.,a paging channel (PCH) and a downlink-shared channel (DL-SCH), uplinkscheduling grant, HARQ information, etc. The PCH and the DL-SCH aretransmitted through the PDSCH. Accordingly, the base station and theuser equipment respectively transmit and receive data through the PDSCHexcept for specific control information or specific service data.Information as to user equipment(s) (one user equipment or a pluralityof user equipments) to which data of the PDSCH are transmitted, andinformation as to how the user equipment(s) receives and decodes PDSCHdata are transmitted through the PDCCH. For example, it is assumed thata specific PDCCH is CRC masked with radio network temporary identity(RNTI) “A,” and information of data transmitted using a radio resource(for example, frequency location) “B” and transmission formatinformation (for example, transport block size, modulation mode, codinginformation, etc.) “C” is transmitted through a specific subframe. Inthis case, one or more user equipments located in a corresponding cellmonitor the PDCCH using their RNTI information, and if there are one ormore user equipments having RNTI “A”, the user equipments receive thePDCCH and receive the PDSCH indicated by “B” and “C” through informationof the received PDCCH.

FIG. 6( a) and FIG. 6( b) illustrate resource units used to configure acontrol channel. FIG. 6( a) illustrates that the number of transmittingantennas is 1 or 2, and FIG. 6( b) illustrates that the number oftransmitting antennas is 4. Depending on the number of transmittingantennas, reference signal patterns are different but establishing aresource unit related to a control channel is identical. Referring toFIG. 6( a) and FIG. 6( b), a basic resource unit of the control channelis REG. The REG includes four neighboring resource elements excludingthe reference signals. The REG is illustrated with a solid line. ThePCFICH and the PHICH includes four REGs and three REGs, respectively.The PDCCH is configured in a unit of CCE, one CCE including nine REGs.

The user equipment is established to identify M(L)(≧L) number of CCEsarranged continuously or arranged by a specific rule, whereby the userequipment can identify whether the PDCCH of L number of CCEs istransmitted thereto. A plurality of L values can be considered by theuser equipment to receive the PDCCH. CCE sets to be identified by theuser equipment to receive the PDCCH will be referred to as a PDCCHsearch space. For example, the LTE system defines the PDCCH search spaceas expressed in Table 1.

TABLE 1 Number Search space S_(k) ^((L)) of PDCCH Aggre- Size candidatesType gation level L [in CCEs] M^((L)) DCI formats UE- 1 6 6 0, 1, 1A,1B, 2 specific 2 12 6 4 8 2 8 16 2 Common 4 16 4 0, 1A, 1C, 3/3A 8 16 2

In Table, L represents the number of CCEs constituting the PDCCH, S_(k)^((L)) represents a PDCCH search space, and M^((L)) represents thenumber of PDCCH candidates to be monitored in the search space.

The PDCCH search space can be divided into a UE-specific search spacethat allows access to only a specific user equipment and a common searchspace that allows access to all user equipments within a cell. The userequipment monitors a common search space in L=4 and 8, and monitors aUE-specific search space in L=1, 2, 4 and 8. The common search space andthe UE-specific search space can be overlapped with each other.

Furthermore, as for the PDCCH search space given to a certain userequipment for each L value, the location of the first CCE (i.e., CCEhaving the smallest index) is varied per subframe depending on the userequipment. This will be referred to as a PDCCH search space hashing.

FIG. 7 is a diagram illustrating an example of a control channel element(CCE) distributed into a system band. Referring to FIG. 7, a pluralityof logically continued CCEs are input to an interleaver. The interleaverperforms interleaving of the plurality of CCEs in a unit of REG.Accordingly, the frequency/time resources constituting one CCE arephysically distributed into all frequency/time regions within thecontrol region of the subframe. As a result, although the controlchannel is configured in a unit of CCE, since interleaving is performedin a unit of REG, frequency diversity and interference randomizationgain can be maximized.

FIG. 8 is a diagram illustrating carrier aggregation (or bandwidthaggregation). The carrier aggregation means that a plurality offrequency blocks are used as a huge logical frequency band so that thewireless communication system uses a wider frequency band.

Referring to FIG. 8, in the wideband system, all system bandwidths (BW)are logical bandwidths and have a bandwidth of 100 MHz. The systembandwidths include five basic frequency blocks, each of which has abandwidth of 20 MHz. The basic frequency block includes one or morephysically consecutive subcarriers. Hereinafter, the basic frequencyblock will simply be referred to as a frequency block. Although it isassumed that the respective frequency blocks have the same bandwidth,this is only exemplary and the frequency blocks can have differentsizes. Also, although it is illustrated that the respective frequencyblocks adjoin to each other in the frequency region, this illustrationis logically exemplary and the respective frequency blocks mayphysically adjoin to each other or spaced apart from each other. Centercarriers may be used differently for the respective frequency blocks, orone common center frequency may be used to physically adjoined frequencyblocks. For example, if it is assumed that all frequency blocksphysically adjoin to one another in FIG. 8, center carrier A can beused. Also, if it is assumed that all frequency blocks physically do notadjoin to one another in FIG. 8, center carrier A, center carrier B andthe like can be used separately for the respective frequency blocks. Thebandwidth of each frequency block can be established in the same manneras the system bandwidth of the legacy system. As the bandwidth of thefrequency block is based on the legacy system, it is possible tofacilitate backward compatibility and system design in a radiocommunication environment where an evolved user equipment and a legacyuser equipment coexist. For example, if the LTE-A system supportscarrier aggregation, bandwidths of the respective frequency blocks canbe established in the same manner as the system bandwidths of the LTEsystem. In this case, the bandwidth of each frequency block can have anyone of 1.25, 2.5, 5, 10, 20 MHz, and their multiple numbers.

If the whole system bandwidth is extended by frequency aggregation, thefrequency bandwidth used for communication of user equipments is definedin a unit of frequency block. User equipment A can use 100 MHz which isthe whole system bandwidth, and performs communication using all of fivefrequency blocks. User equipments B₁ to B₅ can use only a bandwidth of20 MHz and perform communication using one frequency block. Userequipments C₁ to C₂ can use a bandwidth of 40 MHz and performcommunication using two frequency blocks. The two frequency blocks maylogically/physically adjoin to each other or not. The user equipment C₁represents that two frequency blocks which do not adjoin are used, theuser equipment C₂ represents that two frequency blocks which adjoin toeach other are used. Also, although not shown, among a total offrequency blocks, one or more frequency blocks can be used as the systemblocks of the legacy block to support the legacy user equipment.

FIG. 9 to FIG. 11 are block diagrams illustrating a transmitter and areceiver for carrier aggregation. PHY0, PHY1, . . . , PHY n−1 representphysical layers of the respective frequency blocks. Carrier 0, carrier1, . . . , carrier n−1 represent center carriers. Although thesedrawings illustrate that separate center carrier is used per frequencyblock, the same center carrier may be used for a plurality of frequencyblocks which physically adjoin to one another.

Referring to FIG. 9, in a transmitter (a), one MAC entity manages aplurality of frequency blocks. The MAC entity means a functionalunit/block performed by a media access control (MAC) layer. In case ofthe 3GPP LTE system, the MAC layer is connected with a lower layer,i.e., a physical layer through a transport channel, and is connectedwith an upper layer, i.e., a radio link control (RLC) layer through alogical channel. The MAC layer serves to map various logical channelswith various transport channels, and supports resource scheduling, HARQaction, etc. A data block transferred to the physical layer through thetransport channel will be referred to as a transport block. Thetransport block corresponds to a minimum data unit allocated by ascheduler of the MAC layer to the physical layer per data transmission.Although FIG. 9 illustrates that different transport blocks aretransferred through different frequency blocks, this is exemplary andthe same transport block may be transmitted through a plurality offrequency blocks.

Referring to FIG. 10, in the transmitter (a), one MAC entity manages onefrequency block. Namely, the MAC layer and the physical layer have aone-to-one mapping relation. Referring to FIG. 11, in the transmitter(a), among a plurality of MAC entities, a first MAC entity manages onefrequency block and a second MAC entity manages two or more frequencyblocks. Namely, the transmitter of FIG. 11 manages/performs frequencyaggregation in a hybrid type of FIG. 9 and FIG. 10. Accordingly, the MAClayer and the physical layer represent a one-to-one mapping relation ora one-to-multiple mapping relation. In FIG. 9 to FIG. 11, a receiver (b)is configured in a reverse manner of the transmitter (a).

FIG. 12 is a diagram illustrating a structure of a radio frame to whichcarrier aggregation is applied.

Referring to FIG. 12, the LTE-A system can extend the system bandwidthby binding frame structures N defined in the LTE system. In this case,each frame structure is transmitted and received through itscorresponding frequency block. For a radio frame structure of the LTEsystem block, refer to FIG. 4. For convenience, FIG. 12 illustrates onlya downlink frame structure that supports a frequency division dulplex(FDD) mode. Since user equipments that support the LTE system only cantransmit and receive data through one of N number of frequency blocks,the PDCCH search space should be limited to the control region withineach frequency block. Also, PDCCH hashing should follow the existing LTEstructure. Specifically, the PDCCH search space for user equipments thatsupports the LTE system only can be limited to the control region withina specific frequency block established as a system block of the legacysystem among all frequency blocks.

However, such a limitation is not required for the LTE-A user equipmentsthat can be operated in the extended wideband communication system.Accordingly, in respect of the PDCCH search space, two methods can beconsidered. The first method is to distribute the PDCCH search spaceover a plurality of frequency blocks without limitation to a specificfrequency block. Namely, one control region is established for aplurality of frequency blocks. The first method can increase frequencydiversity and interference randomization gain by using the plurality offrequency blocks. The second method is to limit the PDCCH search spaceto a specific frequency block. Namely, a control region is establishedindependently per frequency block, and the PDCCH search space isestablished within the independent control region. In this case, PDCCHhashing is established per frequency block. The second method isadvantageous for backward compatibility for LTE user equipment andsystem design. In this case, frequency diversity and interferencerandomization gain may be more reduced at a specific transmission timeas compared with the first method. However, as the time passes, thefrequency block where the PDCCH search space is established is changed,whereby frequency diversity and interference randomization gain can beobtained. The method will be described in detail with reference to FIG.13 to FIG. 18.

Although this embodiment is described using the PDCCH, this is onlyexemplary and the embodiment may equally be applied to the PHICH.Namely, the PHICH may be distributed into a plurality of frequencyblocks, or may be limited to a specific frequency block. The embodimentof the present invention can be applied to all cases where a controlchannel is transmitted using a plurality of frequency blocks.

Meanwhile, although the system bandwidth includes N number of frequencyblocks, the frequency band that can be received by a specific userequipment can be limited to M(<N) number of frequency blocks. Herein,the value N may be replaced with a value M established differently peruser equipment. For convenience, frequency block indexes 0, 1, 2, . . ., N−1 are given to the N number of frequency blocks, and the frequencyblocks are expressed by n. Also, the number of CCEs existing infrequency block n within a certain subframe is expressed by N_CCE(n).For example, N_CCE(2) represents the number of CCEs existing infrequency block 2. As the case may be, N_CCE(n) may be limited to someCCE not all CCEs existing in frequency block n.

FIG. 13 is a diagram illustrating an example of establishing a physicaldownlink control channel (PDCCH) search space in accordance with oneembodiment of the present invention. In this embodiment, CCE indexes aredefined continuously over N number of frequency blocks. Namely, for userequipments that can receive the PDCCH through N number of frequencyblocks, CCE indexes can be defined continuously over N number offrequency blocks.

For example, CCE indexes are allocated continuously within one frequencyblock. If CCE indexes are all given to CCEs within the correspondingfrequency block, subsequent CCE indexes are allocated to CCEs of nextfrequency block. For example, CCE indexes 0˜N_CCE(0)−1 are allocated toCCE of frequency block 0. Afterwards, CCE indexesN_CCE(0)˜N_CCE(0)+N_CCE(1)−1 are allocated to CCEs of frequency block 1,and CCE indexes N_CCE(0)+N_CCE(1)˜N_CCE(0)+N_CCE(1)+N_CCE(2)−1 areallocated to CCEs of frequency block 2. In this way, indexes can beallocated continuously to CCEs within a plurality of frequency blocks.It is assumed that PDCCH includes L number of CCEs. In this case, thePDCCH search space can be defined with M(L) number of CCEs continued orarranged by a specific rule, based on CCE indexes allocated continuouslyfor N number of frequency blocks. Also, PDCCH search space hashing canbe defined for N number of frequency blocks.

In detail, FIG. 13 illustrates an example of N=3, N_CCE(0)=8, N_CCE(1)=6and N_CCE(2)=7. In this case, it is assumed that one PDCCH includes CCEsof continued indexes, and the number of CCEs included in each frequencyblock is constant regardless of subframe. However, this assumption issimplified for illustration, and the number of CCEs included in eachfrequency block, the number of CCEs constituting PDCCH, PDCCH searchspace, PDCCH hashing, etc. can be established variously depending on acommunication status. In case of FIG. 13, CCE indexes of 0˜20 arecontinuously given to three frequency blocks {0-7: 8-13: 14-20}. ThePDCCH search space includes five CCEs which are continued, and its startlocation is changed in the order of CCE 1=>CCE 13=>CCE 6 depending onsubframe. Namely, the PDCCH search space and hashing are defined for aplurality of frequency blocks.

In this embodiment, since a PDCCH search space for a certain userequipment can be limited to one or a small number of frequency blocks ata specific time, frequency diversity gain may not be great. However,since the PDCCH search space is changed to a certain location of Nnumber of frequency blocks by hashing per subframe, interferencerandomization effect can be obtained.

FIG. 14 is a diagram illustrating an example of establishing a PDCCHsearch space in accordance with another embodiment of the presentinvention. In this embodiment, the PDCCH search space is distributedinto N number of frequency blocks. Namely, if one PDCCH includes Lnumber of CCEs, for a certain user equipments that can receive the PDCCHthrough N number of frequency blocks, M(L) number of CCEs constitutingthe PDCCH search space can be distributed into N number of frequencyblocks in a random manner.

For example, frequency block indexes and CCE indexes within eachfrequency block are combined with each other for N_CCE(0), N_CCE(1), . .. N_CCE(N−1) number of CCE indexes existing in N number of differentfrequency blocks, whereby new indexes can be allocated to a total ofN_CCE(0)+N_CCE(1)+ . . . +N_CCE(N−1) number of CCEs. New indexes can bedefined in such a manner that CCEs of continued indexes are distributedinto a certain frequency blocks of N number of frequency blocks, notnecessarily into the same frequency block. It is assumed that PDCCHincludes L number of CCEs. In this case, the PDCCH search space can bedefined for M(L) number of CCEs logically continued or arranged by aspecific rule, based on CCE indexes newly given for N number offrequency blocks. Also, PDCCH search space hashing can be defined for Nnumber of frequency blocks based on the newly given CCE indexes.

In detail, FIG. 14 illustrates an example of N=3, N_CCE(0)=8, N_CCE(1)=6and N_CCE(2)=7. In this case, it is assumed that one PDCCH includes CCEsof continued indexes, and the number of CCEs included in each frequencyblock is constant regardless of subframe. However, this assumption issimplified for illustration, and the number of CCEs included in eachfrequency block, the number of CCEs constituting PDCCH, PDCCH searchspace, PDCCH hashing, etc. can be established variously depending on acommunication status. In case of FIG. 14, the newly given CCE indexesare given to three frequency blocks in a manner of {0,3,6,9,11,14,17,19:1,5,7,12,15,20: 2,4,8,10,13,16,18}. The PDCCH search space includes fiveCCEs which are continued, and its start location is changed in the orderof CCE 0=>CCE 15=>CCE 20 depending on subframe. Namely, the PDCCH searchspace and hashing are defined for a plurality of frequency blocks.Particularly, the PDCCH search space is distributed within a pluralityof frequency blocks in a unit of CCE.

In this embodiment, since the PDCCH for a certain user equipment isdistributed into N number of frequency blocks in a unit of CCE at aspecific time, frequency diversity and interference randomization gaincan be obtained. Also, since the PDCCH search space and hashing aredefined for N number of frequency blocks, frequency diversity andinterference randomization gain can be obtained.

FIG. 15 is a diagram illustrating an example of establishing a PDCCHsearch space in accordance with still another embodiment of the presentinvention. In this embodiment, the location of the PDCCH search space ishopped into one of N number of frequency blocks depending on time.

For example, for a certain user equipment that can receive the PDCCHthrough N number of frequency blocks, a control region, PDCCH searchspace, and PDCCH search space hashing can be defined within onefrequency block like the existing 3GPP LTE. In this case, a specificfrequency block where the PDCCH search space for the user equipmentexists can be changed according to a random pattern per subframe or in aunit of a certain number of subframes. Also, the specific frequencyblock can be changed according to a certain pattern. The certain patterncan be shared between the base station and the user equipment throughsystem information, radio resource control (RRC) signaling, etc. Thecertain pattern can be a predetermined one, or can be generated inaccordance with a given rule. The certain pattern can be determined orindirectly indicated using information shared between the base stationand the user equipment. For example, the certain pattern can bedetermined or indirectly indicated using at least one of user equipmentidentifier, base station identifier, and frequency bandwidth (forexample, the number of frequency blocks). If the certain pattern ispreviously determined, the base station and the user equipment maypreviously store a plurality of patterns therein. In this case,information of the certain pattern can be shared using index indicatinga specific pattern of a plurality of patterns. The certain pattern canbe repeated with a given period that can be defined in a unit of amultiple of subframe or multiple of radio frame. Since the frequencyblock through which the PDCCH is transmitted is varied depending ontime, the frequency block which the corresponding user equipment triesdecoding is also varied depending on time. Also, a change pattern of thefrequency block to which the PDCCH is transmitted can be establisheddifferently per user equipment. Also, a hashing pattern of the PDCCHsearch space can be established differently even for the same userequipment within each frequency block.

In detail, FIG. 15 illustrates an example of N=3, N_CCE(0)=8, N_CCE(1)=6and N_CCE(2)=7. In this case, it is assumed that one PDCCH includes CCEsof continued indexes, and the number of CCEs included in each frequencyblock is constant regardless of subframe. However, this assumption issimplified for illustration, and the number of CCEs included in eachfrequency block, the number of CCEs constituting PDCCH, PDCCH searchspace, PDCCH hashing, etc. can be established variously depending on acommunication status. In case of FIG. 15, CCE indexes are independentlygiven to each frequency block and continuously given within eachfrequency block {0-7: 0-5: 0-6}. The PDCCH search space includes fiveCCEs which are continued, and its start location is changed in the orderof (frequency block 0, CCE 1)=>(frequency block 2, CCE 2)=>(frequencyblock 1, CCE 0) depending on subframe. Namely, the PDCCH search spaceand hash are defined within the frequency blocks.

In this embodiment, since the PDCCH for a certain user equipment existsin only one frequency block at a specific time, frequency diversity gaincannot be obtained. However, since the frequency block to which thePDCCH is transmitted is varied in accordance with the lapse of time,frequency diversity and interference randomization gain can be obtainedbased on a given time interval.

FIG. 16 is a diagram illustrating an example of mapping a controlchannel with each frequency block in accordance with one embodiment ofthe present invention. For convenience, the method of FIG. 15 is used.According to the method of FIG. 15, the control region is establishedindependently per frequency block. Accordingly, the control channel isalso established independently per frequency block. Examples of thecontrol channel include, but not limited to, PDCCH, PHICH, and PCFICH.For convenience, the PDCCH will be described as an example of thecontrol channel. The PDCCH includes one or more CCEs. A plurality ofPDCCHs constitute a PDCCH search space for a specific user equipment.

Referring to FIG. 16, in the wideband system, the whole system bandincludes a plurality of frequency blocks. The bandwidth of eachfrequency block can be established based on a system band of anarrowband system. For example, each frequency block can be establishedto have the same size as that of the system block of the LTE which isthe legacy system. When the PDCCH is mapped with the physical channel,the PDCCH is interleaved in a unit of REG through the interleaver andthen distributed within the frequency band. Since the PDCCH isestablished independently per frequency block, the interleaver isoperated in a unit of frequency block. In detail, FIG. 6 illustratesthat the system band of the wideband system includes four frequencyblocks and the interleaver operated in a unit of REG per frequency blockis used. There is not limitation in the number of frequency blocks wherethe PDCCH is established for a specific user equipment at a specifictime. However, in the embodiment of the present invention, it is assumedthat the number of frequency blocks where the PDCCH is established for aspecific user equipment is smaller than a total of frequency blocks.Extremely, the number of frequency blocks where the PDCCH is establishedfor a specific user equipment may be one. For example, as the timepasses, the frequency block where the PDCCH is established can beestablished in such a manner as {frequency block 0, frequency block1}=>{frequency block 0, frequency block 3}=>{frequency block 1,frequency block 2, frequency block 3}. Also, as the time passes, thefrequency block where the PDCCH is established can be established insuch a manner as {frequency block 1}=>{frequency block 0}=>{frequencyblock 3}. Although hash of the PDCCH search space is performedindependently per frequency block, it is not illustrated in detail inFIG. 16.

For convenience, the block diagram of FIG. 16 illustrates an example ofimplementing the method of FIG. 15. However, this is only exemplary, andthe block diagram of FIG. 16 can easily be varied to implement themethods of FIG. 13 and FIG. 14. For example, for application to themethod of FIG. 13, FIG. 16 can be varied in such a manner that the wholesystem band includes one interleaver. Also, for application to themethod of FIG. 14, FIG. 16 can be varied in such a manner that the wholesystem band includes a first interleaver operated in a level of CCE anda second interleaver operated in a level of REG for CCE output from thefirst interleaver.

FIG. 17 is a diagram illustrating an example of establishing a PDCCHsearch space within a plurality of frequency blocks in accordance withone embodiment of the present invention. For convenience, it is assumedthat the respective frequency blocks include the same number of CCEs. Itis also assumed that the size of the PDCCH search space is constantregardless of frequency block and subframe. Furthermore, it is assumedthat the PDCCH is established for one frequency block at a specifictransmission time.

Referring to FIG. 17, a specific user equipment can receive the PDCCHthrough all frequency blocks or some frequency blocks. The number offrequency blocks that can receive the PDCCH can be determined dependingon user equipment capability, data transmission requirements, userpolicies, etc. When a specific user equipment can receive the PDCCHthrough all frequency blocks (case 1), a specific frequency block wherethe PDCCH search space is established for the user equipment can bechanged in a unit of subframe. Meanwhile, when a specific user equipmentcan receive the PDCCH through some frequency blocks (cases 2 and 3), aspecific frequency block where the PDCCH search space is established forthe user equipment can be changed in a unit of subframe within thecorresponding some frequency blocks. For the method of changing thespecific frequency block, refer to the description of FIG. 15. Also, thefirst CCE index where the PDCCH search space starts can be changeddepending on transmission time and/or frequency block and/or userequipment.

FIG. 18 is a diagram illustrating an example of transmitting orreceiving data to and in a user equipment in accordance with controlinformation in accordance with one embodiment of the present invention.For convenience, it is assumed that the system band of the widebandsystem includes two frequency blocks. Also, frequency blocks are notillustrated separately for an uplink.

Referring to FIG. 18, the user equipment and the base station shareinformation of a pattern of the PDCCH search space (S1810). In thiscase, the pattern of the PDCCH search space includes a pattern of aspecific frequency block where the PDCCH or the PDCCH search space isestablished or a hash pattern of the PDCCH search space. The informationof the pattern can be indicated directly, or can be indicated indirectlyusing other information shared between the user equipment and the basestation. Also, the information of the pattern can be shared between theuser equipment and the base station through system information, RRCsignaling, etc. At the first time, the user equipment receives an uplink(UL) scheduling signal included in the PDCCH through frequency block(Freq Blk) 0 (S1820). In this case, the user equipment performs ULtransmission using time/frequency resources indicated by the basestation in accordance with the UL scheduling signal (S1830). Thefrequency resource for UL transmission may not need to be the same asthe frequency block where the UL scheduling information is received.Afterwards, at the second or fourth time, the user equipment receives adownlink (DL) scheduling signal included in the PDCCH through frequencyblock 0 or frequency block 1 (S1840, S1860, and S1880). In this case,the user equipment receives DL transmission using time/frequencyresources indicated by the base station in accordance with the DLscheduling signal (S1850, S1870 and S1890). The frequency resource forDL transmission may not need to be the same as the frequency block wherethe DL scheduling information is received. For example, if the userequipment receives the DL scheduling signal from frequency block 0, DLtransmission can be performed through frequency block 0 and/or frequencyblock 1. Likewise, if the user equipment receives the DL schedulingsignal from frequency block 1, DL transmission can be performed throughfrequency block 0 and/or frequency block 1.

As illustrated in FIG. 18, in the wireless communication system, thebase station controls data transmission and reception of the userequipment. Namely, for downlink data, the base station transmitsdownlink scheduling information to the corresponding user equipment tonotify the corresponding user equipment of time/frequency regions wheredata will be transmitted, encoding scheme, data size, HARQ relatedinformation, etc. Also, in order that the user equipment transmitsuplink data to the base station, the base station transmits uplinkscheduling information to the corresponding user equipment to notify thecorresponding user equipment of time/frequency regions that can be usedby the corresponding user equipment, encoding scheme, data size, HARQrelated information, etc. In the LTE system, scheduling information istransmitted to the user equipment through the PDCCH.

For convenience, the information of the time/frequency regions wheredata will be transmitted will be referred to as resource allocation (RA)information, the information of data size will be referred to astransport block (Trblk) information, and the HARQ related informationwill be referred to as HARQ information. Generally, it is assumed thatone HARQ process processes one transport block. Also, a plurality oftransport blocks can be transmitted and received to and in one userequipment in such a manner that they are spatially multiplexed in amultiple input multiple output (MIMO) transmission and reception mode.For convenience, a bundle of transport blocks which are bound throughspatial multiplexing in a MIMO transmission/reception will be defined asa transport block bundle. In this case, the transport block bundle mayinclude one transport block when spatial multiplexing is not applied.

For an example of the aforementioned information, in case of the LTEsystem, the resource allocation information can include various kinds ofinformation such as resource allocation format, location/size oftime/frequency resources, and resource hopping. The resource allocationformat can indicate unit of time/frequency resources and information oflocation relation between time/frequency resources. The time/frequencyresources can be indicated using a bitmap in a unit of resource block orresource block group. The transport black information can includevarious kinds of information such as data size and modulation and codingscheme. The data size can be indicated directly, or can be indicatedindirectly using allocated resources and modulation degree. The HARQinformation includes various kinds of information such as HARQ processnumber, the presence of new data, and redundancy version (RV). Thescheduling information can include codebook information and MIMOinformation related to a precoding matrix indicator (PMI). To configurethe scheduling information, examples of the aforementioned informationcan be bound in a given order to form one bit stream. The formed bitstream can be transmitted to the corresponding user equipment throughthe PDCCH after undergoing CRC masking using RNTI, channel coding andrate matching.

If communication is performed using a plurality of frequency blocks,scheduling information transmitted through the control channel can beconfigured by two methods. According to the first method, scheduling isperformed independently per frequency block. For example, schedulinginformation transmitted through the PDCCH can indicate resourceallocation information only for one frequency block. In this case, it ispossible to backward compatibility for the legacy user equipment thatsupports narrowband transmission and reception only. According to thesecond method, scheduling is performed by binding a plurality offrequency blocks. For example, the scheduling information transmittedthrough the PDCCH can indicate resource allocation information of aplurality of frequency blocks. In this case, limited resources of thecontrol region can be used efficiently. Also, there is no need toreceive all frequency blocks to receive the PDCCH.

It is possible to easily implement the first method by modifying thesecond method. Accordingly, the second method will be described indetail with reference to the accompanying drawings.

FIG. 19 to FIG. 20 are diagrams illustrating an example of configuringscheduling information of a plurality of frequency blocks in accordancewith one embodiment of the present invention. In this embodiment,different transport block bundles are allocated to different frequencyblocks. For convenience, it is assumed that the number of frequencyblocks that can be used for transmission and reception within the systemband of the wideband system by a specific user equipment is M(≦N). Inthis case, N represents the number of all frequency blocks. M can beestablished for each user equipment in accordance with transmission andreception capability of the user equipment or decision of the basestation.

The user equipment is established for each of M number of frequencyblocks to transmit and receive different transport block bundles. Inthis case, for the same user equipment, HARQ process is operatedindependently for different frequency blocks. For example,retransmission of a transport block where initial transmission isperformed through frequency block 1 and retransmission of a transportblock where initial transmission is performed through frequency block 2are performed independently at the same time. Of course, differenttransport blocks constituting one transport block bundle within the samefrequency block can be operated independently through their independentHARQ process. Specifically, the uplink/downlink scheduling informationcan be defined by two different methods illustrated in FIG. 19 and FIG.20.

FIG. 19 illustrates that scheduling information is assigned only for afrequency block where actual data transmission and reception isperformed at a certain time. Referring to FIG. 19, the schedulinginformation includes information (f-block usage) 1910 indicating acorresponding one of N or M number of frequency blocks, through whichdata transmission and reception is performed, transport block bundleinformation (Trblk) 1920 transmitted through each frequency block whenthe number of frequency blocks where actual data transmission andreception is performed at the corresponding time is n, HARQ information1930, and resource allocation (RA) information 1940. The schedulinginformation can further include other information (for example, MIMOrelated information) if necessary. A combination order of informationcan be determined optionally. Particularly, the f-block usageinformation 1910 can be defined in a bitmap of N or M bits for N or Mnumber of frequency blocks. In this case, amount of required informationcan be flexibly modified depending on the number of frequency blocksactually scheduled to the corresponding user equipment at a certaintime. Accordingly, it is advantageous in that overhead of schedulinginformation signaling can be optimized. On the other hand, since theuser equipment does not know the number of frequency blocks which willbe scheduled thereto, a problem occurs in that formats of schedulinginformation to be searched by the user equipment increase.

FIG. 20 illustrates that scheduling information is always assigned for Nor M number of frequency blocks. Referring to FIG. 20, the schedulinginformation always includes Trblk information 2020 of N or M number offrequency blocks, HARQ information 2030, and resource allocation (RA)information 2040. The scheduling information can further include otherinformation (for example, MIMO related information) if necessary. Acombination order of information can be determined optionally. In thiscase, even though the base station schedules frequency blocks smallerthan N or M number of frequency blocks to the user equipment at acertain time, since scheduling information transmitted to the userequipment always includes scheduling information of N or M number offrequency blocks, signaling overhead of scheduling information becomeshigher. On the other hand, since scheduling information is not varieddepending on the number of frequency blocks which are scheduled, it isadvantageous in that formats of scheduling information to be searched bythe user equipment are reduced.

FIG. 21 to FIG. 22 are diagrams illustrating an example of configuringscheduling information of a plurality of frequency blocks in accordancewith another embodiment of the present invention. In this embodiment,transport block bundles are allocated regardless of frequency blocks.For convenience, it is assumed that the number of frequency blocks thatcan be used for transmission and reception within the system band of thewideband system by a specific user equipment is M(N). In this case, Nrepresents the number of all frequency blocks. M can be established foreach user equipment in accordance with transmission and receptioncapability of the user equipment or decision of the base station. One ora plurality of transport block bundles can be transmitted usingdifferent frequency blocks together without discriminating individualfrequency block at a certain time. Specifically, the uplink/downlinkscheduling information can be defined by two different methodsillustrated in FIG. 21 and FIG. 22.

FIG. 21 illustrates that scheduling information is assigned only for afrequency block where actual data transmission and reception isperformed at a certain time. Referring to FIG. 21, the schedulinginformation includes f-block usage information 2110, Trblk information2120 for transport block bundle, and HARQ information 2130. Also, thescheduling information includes n number of resource allocation (RA)information 2140 indicating resource allocation of each frequency blockwhen the number of frequency blocks allocated at a corresponding time isn. The scheduling information can further include other information (forexample, MIMO related information) if necessary. A combination order ofinformation can be determined optionally. Particularly, the f-blockusage information 2110 can be defined in a bitmap of N or M bits for Nor M number of frequency blocks. In this case, amount of requiredinformation can be flexibly modified depending on the number offrequency blocks actually scheduled to the corresponding user equipmentat a certain time. Accordingly, it is advantageous in that overhead ofscheduling information signaling can be optimized. On the other hand,since the user equipment does not know the number of frequency blockswhich will be scheduled thereto, a problem occurs in that formats ofscheduling information to be searched by the user equipment increase.

FIG. 22 illustrates that scheduling information is always assigned for Nor M number of frequency blocks. Referring to FIG. 22, the schedulinginformation includes Trblk information 2220, HARQ information 2230, andresource allocation (RA) information 2240 for N or M number of frequencyblocks. The scheduling information can further include other information(for example, MIMO related information) if necessary. A combinationorder of information can be determined optionally. In this case, eventhough the base station schedules frequency blocks smaller than N or Mnumber of frequency blocks to the user equipment at a random time, sincescheduling information transmitted to the user equipment always includesscheduling information of N or M number of frequency blocks, signalingoverhead of scheduling information becomes higher. On the other hand,since scheduling information is not varied depending on the number offrequency blocks which are scheduled, it is advantageous in that formatsof scheduling information to be searched by the user equipment arereduced.

FIG. 23 to FIG. 24 are diagrams illustrating an example of configuringscheduling information of a plurality of frequency blocks in accordancewith still another embodiment of the present invention. In thisembodiment, frequency blocks are freely mapped with transport blockbundles. For convenience, it is assumed that the number of frequencyblocks that can be used for transmission and reception within the systemband of the wideband system by a specific user equipment is M(≦N). Inthis case, N represents the number of all frequency blocks. M can beestablished for each user equipment in accordance with transmission andreception capability of the user equipment or decision of the basestation. m(1≦m≦n) number of transport block bundles can be transmittedand received in one user equipment through n number of frequency blocksat a certain time. Specifically, the uplink/downlink schedulinginformation can be defined by two different methods illustrated in FIG.23 and FIG. 24.

FIG. 23 illustrates that scheduling information is assigned only for afrequency block where actual data transmission and reception isperformed at a certain time. Referring to FIG. 23, the schedulinginformation includes information (m) 2300 of the number of scheduledtransport block bundles, f-block usage information 2310, Trblkinformation 2320 for m number of transport block bundles, HARQinformation 2330, RA information 2340 for n number of frequency blocks,and information (Trblk to f-block) 2350 of mapping m number of transportblock bundles with n number of frequency blocks. The schedulinginformation can further include other information (for example, MIMOrelated information) if necessary. A combination order of informationcan be determined optionally. Particularly, the f-block usageinformation 2310 can be defined in a bitmap of N or M bits for N or Mnumber of frequency blocks. For another example, instead of information(m) 2300 of the number of transport block bundles which are actuallytransmitted, the number of maximum transport block bundles may bepreviously set to m′. In this case, Trblk information 2320 and HARQinformation 2330 of m′, not m, number of transport block bundles may betransmitted. For other example, the user equipment may detect the numberof transport block bundles using different scheduling information sizes.

The Trblk to f-block information 2350 can directly indicate one-to-onemapping relation between transport blocks and frequency blocks. Forexample, frequency blocks where the respective transport blocks areallocated may be indicated using a bit of log₂(M) or log₂(N). Foranother example, the Trblk to f-block information 2350 includes a bitmapof n−1 bits, wherein each bit can indicate a boundary of frequencyblocks with which the respective transport block bundles are mapped. Forexample, it is assumed that two transport block bundles are mapped withfour scheduled frequency blocks. In this case, when the Trblk to f-blockinformation 2350 of 3 bits represents 010, the second bit value of 1ends at a second frequency block of frequency blocks where mapping ofthe first transport block is scheduled, and starts from a thirdfrequency block of frequency blocks where mapping of the secondtransport block is scheduled. At this time, bit values 1 and 0 can bedefined to be interpreted contrary to each other.

In this case, amount of required information can be flexibly modifieddepending on the number of frequency blocks actually scheduled to thecorresponding user equipment at a certain time. Accordingly, it isadvantageous in that overhead of scheduling information signaling can beoptimized. On the other hand, since the user equipment does not know thenumber of frequency blocks which will be scheduled thereto, a problemoccurs in that formats of scheduling information to be searched by theuser equipment increase.

FIG. 24 illustrates that scheduling information is always assigned for Nor M number of frequency blocks. Referring to FIG. 24, the schedulinginformation includes information (m) 2400 of the number of scheduledtransport block bundles, Trblk information 2420 for m number oftransport block bundles, HARQ information 2430, M or N number of RAinformation 2440, and information (Trblk to f-block) 2450 of mapping mnumber of transport block bundles with n number of frequency blocks. Thescheduling information can further include other information (forexample, MIMO related information) if necessary. A combination order ofinformation can be determined randomly. For another example, instead ofinformation (m) 2400 of the number of transport block bundles which areactually transmitted, the number of maximum transport block bundles maybe previously set to m′. In this case, Trblk information 2420 and HARQinformation 2430 of m′, not m, number of transport block bundles may betransmitted. For other example, the user equipment may detect the numberof transport block bundles using different scheduling information sizes.Details of the Trblk to f-block information 2450 are the same as thedescription of FIG. 23.

In this case, even though the base station schedules frequency blockssmaller than N or M number of frequency blocks to the user equipment ata certain time, since scheduling information transmitted to the userequipment always includes scheduling information of N or M number offrequency blocks, signaling overhead of scheduling information becomeshigher. On the other hand, since scheduling information is not varieddepending on the number of frequency blocks which are scheduled, it isadvantageous in that formats of scheduling information to be searched bythe user equipment are reduced.

FIG. 25 is a diagram illustrating a transceiver that can be applied toone embodiment of the present invention. The transceiver could be a partof the base station or the user equipment.

Referring to FIG. 25, the transceiver 2500 includes a processor 2510, amemory 2520, an RF module 2530, a display module 2540, and a userinterface module 2550. The transceiver 2500 is illustrated forconvenience of description, and some modules of the transceiver 2500 maybe omitted. Also, the transceiver may further include required modules.Furthermore, some modules of the transceiver 2500 may be divided intosegmented modules. The processor 2510 is configured to perform theoperation according to the embodiment of the present invention, which isillustrated with reference to the accompanying drawings. In detail, whenthe transceiver 2500 is a part of the base station, the processor 2510can generate a control signal and map the control signal with a controlchannel established within a plurality of frequency blocks. Also, whenthe transceiver 2500 is a part of the user equipment, the processor 2510can identify a control channel indicated thereto from a signal receivedfrom a plurality of frequency blocks and extract a control signal fromthe control channel. Afterwards, the processor 2510 can perform arequired operation based on the control signal. For the detailedoperation of the processor 2510, refer to the description of FIG. 1 toFIG. 24. The memory 2520 is connected with the processor 2510 and storesoperating system, application, program code, data, etc. therein. The RFmodule 2530 is connected with the processor 2510 and converts a basebandsignal to a radio signal or vice versa. To this end, the RF module 2530performs analog conversion, amplification, filtering, frequency unlinkconversion or their reverse procedures. The display module 2540 isconnected with the processor 2510, and displays various kinds ofinformation. Examples of the display module 2540 include, but notlimited to, LCD(Liquid Crystal Display), LED(Light Emitting Diode), andOLED(Organic Light Emitting Diode). The user interface module 2550 isconnected with the processor 2510, and can be configured by combinationof well known user interfaces such as key pad and touch screen.

The aforementioned embodiments are achieved by combination of structuralelements and features of the present invention in a predetermined type.Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment. Moreover, it will be apparent that someclaims referring to specific claims may be combined with another claimsreferring to the other claims other than the specific claims toconstitute the embodiment or add new claims by means of amendment afterthe application is filed.

The embodiments of the present invention have been described based onthe data transmission and reception between the base station and theuser equipment. A specific operation which has been described as beingperformed by the base station may be performed by an upper node of thebase station as the case may be. In other words, it will be apparentthat various operations performed for communication with the userequipment in the network which includes a plurality of network nodesalong with the base station can be performed by the base station ornetwork nodes other than the base station. The base station may bereplaced with terms such as a fixed station, Node B, eNode B (eNB), andaccess point. Also, the user equipment may be replaced with terms suchas mobile station (MS) and mobile subscriber station (MSS).

The embodiments according to the present invention may be implemented byvarious means, for example, hardware, firmware, software, or theircombination. If the embodiment according to the present invention isimplemented by hardware, the random access method in the wirelesscommunication system according to the embodiment of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, etc.

If the embodiment according to the present invention is implemented byfirmware or software, the method of processing data in a wirelesscommunication system according to the embodiment of the presentinvention may be implemented by a type of a module, a procedure, or afunction, which performs functions or operations described as above. Asoftware code may be stored in a memory unit and then may be driven by aprocessor. The memory unit may be located inside or outside theprocessor to transmit and receive data to and from the processor throughvarious means which are well known.

It will be apparent to those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit and essential characteristics of the invention. Thus, theabove embodiments are to be considered in all respects as illustrativeand not restrictive. The scope of the invention should be determined byreasonable interpretation of the appended claims and all change whichcomes within the equivalent scope of the invention are included in thescope of the invention.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a wireless communication systemthat uses a plurality of frequency blocks. The wireless communicationsystem can support at least one of SC-FDMA (Single Carrier-FrequencyDivision Multiple Access), MC-FDMA (Multi Carrier-Frequency DivisionMultiple Access) and OFDMA (Orthogonal Frequency Division MultipleAccess). The wireless communication system can support at least one ofFDD (Frequency Division Duplex), H-FDD (Half-FDD) and TDD (Time DivisionDuplex). In detail, the present invention can be applied to a method ofsignaling control information in the wireless communication system.

What is claimed is:
 1. A method for performing communication in a userequipment of a wireless communication system, the method comprising:receiving a control region through a specific frequency block of aplurality of frequency blocks, the control region including a pluralityof control channels; identifying a first control channel for the userequipment in the control region; and performing an operation inaccordance with information included in the first control channel,wherein the specific frequency block through which the first controlchannel is transmitted is changed according to a certain pattern withthe lapse of time.
 2. The method of claim 1, wherein the wirelesscommunication system supports carrier aggregation.
 3. The method ofclaim 2, wherein a bandwidth of each frequency block is establishedbased on a bandwidth of a system block defined in a legacy system. 4.The method of claim 2, wherein at least one of all frequency blocks isused as a system block defined in a legacy system.
 5. The method ofclaim 1, wherein center carriers of the respective frequency blocks aredifferent from one another.
 6. The method of claim 1, wherein thecontrol region is configured by one or more consecutive orthogonalfrequency division multiple access (OFDMA) symbols.
 7. The method ofclaim 1, wherein the step of identifying the first control channelincludes identifying a control channel search space established withinthe control region, the control channel search space consisting of someof all control channels.
 8. The method of claim 7, wherein the controlchannel search space includes one or more control channel elements(CCEs).
 9. The method of claim 1, wherein the information included inthe first control channel includes scheduling information.
 10. Themethod of claim 9, wherein data are transmitted and received through ascheduled one of the plurality of frequency blocks, the specificfrequency block being different from the scheduled frequency block. 11.The method of claim 1, wherein the certain pattern is shared between theuser equipment and a base station.
 12. The method of claim 11, whereinthe certain pattern is shared between the user equipment and the basestation through an index indicating a specific pattern.
 13. The methodof claim 11, wherein the certain pattern is determined indirectly usingspecific information shared between the user equipment and the basestation.
 14. The method of claim 13, wherein the specific informationincludes at least one of identifier for identifying the user equipment,identifier for identifying the base station, available frequencybandwidths, and the number of available frequency blocks.
 15. A userequipment for performing communication using a plurality of frequencyblocks, the user equipment comprising: a radio frequency (RF) moduleconfigured to transmit or receive a signal through the plurality offrequency blocks; and a processor configured to process the signalreceived from the RF module per frequency block, wherein the RF modulereceives a control region through a specific one of the plurality offrequency blocks, the control region including a plurality of controlchannels, the processor identifies a first control channel for the userequipment in the control region and performs an operation in accordancewith information included in the first control channel, and the specificfrequency block through which the control region is transmitted ischanged according to a certain pattern with the lapse of time.